Molecular characterization of bovine placental and ovarian 20α-hydroxysteroid dehydrogenase

PTPN11 (SHP2) Is Indispensable for Growth Factors and Cytokine Signal Transduction During Bovine Oocyte Maturation and Blastocyst Development

This study was aimed to investigate the role of SHP2 (Src-homology-2-containing phosphotyrosine phosphatase) in intricate signaling networks invoked by bovine oocyte to achieve maturation and blastocyst development. PTPN11 (Protein Tyrosine Phosphatase, non-receptor type 11) encoding protein SHP2, a positive transducer of RTKs (Receptor Tyrosine Kinases) and cytokine receptors, can play a significant role in bovine oocyte maturation and embryo development, but this phenomenon has not yet been explored. Here, we used different growth factors, cytokines, selective activator, and a specific inhibitor of SHP2 to ascertain its role in bovine oocyte developmental stages in vitro. We found that SHP2 became activated by growth factors and cytokines treatment and was highly involved in the activation of oocyte maturation and embryo development pathways. Activation of SHP2 triggered MAPK (mitogen-activated protein kinases) and PI3K/AKT (Phosphoinositide 3-kinase/Protein kinase B) signaling cascades, which is not only important for GVBD (germinal vesical breakdown) induction but also for maternal mRNA translation. Inhibition of phosphatase activity of SHP2 with PHPS1 (Phenylhydrazonopyrazolone sulfonate 1) reduced oocytes maturation as well as bovine blastocyst ICM (inner cell mass) volume. Supplementation of LIF (Leukemia Inhibitory Factor) to embryos showed an unconventional direct relation between p-SHP2 and p-STAT3 (Signal transducer and activator of transcription 3) for blastocyst ICM development. Other than growth factors and cytokines, cisplatin was used to activate SHP2. Cisplatin activated SHP2 modulate growth factors effect and combine treatment significantly enhanced quality and rate of developed blastocysts.

Data on the localization of EGFP and 20α-hydroxysteroid dehydrogenase (20α-HSD) in the placenta and testes of transgenic mice

In order to investigate the function of monkey 20α-hydroxysteroid dehydrogenase (20α-HSD), transgenic mice (tg) were produced, expressing enhanced green fluorescent protein (EGFP) under the control of the monkey 20α-HSD promoter. The expression levels and localization of EGFP and 20α-HSD were analyzed in immature testis and in placenta. In support of our recent publication, "Characterization of transgenic mice expressing EGFP under control of monkey 20α-hydroxysteroid dehydrogenase promoter" (Park et al., 2018) [1], it was important to characterize the function of EGFP and 20α-HSD in the ovarian luteal cells of tg mice. Here, the expression of EGFP and 20α-HSD in immature testis and placenta are presented. The expression level of EGFP and 20α-HSD were detected in the testes 1 week after birth, and increased dramatically at 8 weeks. Both of proteins strongly detected in the placenta on days 14, 16, and 18 of pregnancy. Immunohistochemical analysis revealed that EGFP was detected in the seminiferous epithelium and 20α-HSD was specifically localized in the seminiferous tubule at 8 weeks.

Characterization of transgenic mice expressing EGFP under the control of the monkey 20α-hydroxysteroid dehydrogenase promoter

To directly assess the molecular function of the monkey 20α-hydroxysteroid dehydrogenase (20α-HSD) promoter, we generated transgenic mice (tg) expressing enhanced green fluorescent protein (EGFP) under control of this promoter. We demonstrated that prostaglandin F₂α induced 20α-HSD promoter activity in CHO cells in a dose-dependent manner. Furthermore, forskolin treatment markedly reduced 20α-HSD promoter activity, and prolactin exhibited weak inhibitory activity. The transgenic mouse obtained one positive founder male. The transgene was propagated in 10 successive generations without any notable defects to the progeny. EGFP and 20α-HSD in the tg mice were colocalized in the luteal cells of the ovary during late pregnancy. Strong EGFP and 20α-HSD protein signals were also detected in the adult testis. Immunohistochemical analysis revealed high EGFP levels in the seminiferous epithelium, whereas 20α-HSD was expressed in the seminiferous tubules. Our data suggest that the ovaries in monkey and mouse exhibit similar expression patterns of 20α-HSD during pregnancy. However, the expression pattern of EGFP in tg mice testis slightly differed from that of the endogenous 20α-HSD. Further investigation is required to elucidate the functional mechanisms underlying regulation of the monkey 20α-HSD promoter in the tg mice.

Production and characterization of monoclonal antibodies against recombinant tethered follicle-stimulating hormone from Japanese eel Anguilla japonica

We prepared monoclonal antibodies (mAbs) against a recombinant tethered follicle-stimulating hormone (rec-FSH) from Japanese eel Anguilla japonica that was produced in Escherichia coli. Positive hybridomas (clones eFA-C5, eFA-C10, eFA-C11, eFA-C12, eFA-C13, and eFB-C14) were selected by using the eel FSH antigen in ELISA, and anti-eel FSH mAbs were purified from culture supernatants by performing affinity chromatography. Three of the 6mAbs were characterized and their isotypes were identified as IgG2b (eFA-C5 and eFA-C11) and IgG1 (eFB-C14). In western blotting assays, the mAbs recognized the antigen as a 24.3-kDa band, and further detected bands of 34 and 32kDa in the supernatants of CHO cells transfected with cDNA encoding tethered eel FSHβ/α and LHβ/α, respectively. PNase F-mediated deglycosylation of the recombinant proteins resulted in a drastic reduction in their molecular weight, to 7-9kDa. The mAbs eFA-C5 and eFA-C11 recognized the eel FSHα-subunit that is commonly encoded among glycoprotein hormones, whereas eFB-C14 recognized the eel FSHβ-subunit, and immunohistochemical analysis revealed that the staining by these mAbs was specifically localized in the eel pituitary. We also established an ELISA system for detecting rec-tethered FSHβ/α and LHβ/α produced from CHO cell lines. Measurement of biological activities in vitro revealed that only weak activity of rec-FSHβ/α was detected. The activity of rec-LHβ/α was found to be increased in a dose-dependent manner for eel oocyte maturation.

Data on the characterization of follicle-stimulating hormone monoclonal antibodies and localization in Japanese eel pituitary

Monoclonal antibodies were generated against recombinant follicle-stimulating hormone (rec-FSH) from Japanese eel Anguilla japonica; rec-FSH was produced in Escherichia coli and purified using Ni-NTA Sepharose column chromatography.

In support of our recent publication, "Production and characterization of monoclonal antibodies against recombinant tethered follicle-stimulating hormone from Japanese eel Anguilla japonica" [1], it was important to characterize the specificity of eel follicle-stimulating hormone antibodies. Here, the production and ELISA system of these monoclonal antibodies are presented. The affinity-purified monoclonal antibodies specifically detected eel rec-FSH in ELISA and on western blots of rec-FSH produced from CHO cells. Immunohistochemical analysis revealed that FSH staining was specifically localized in the eel pituitary.

Lipopolysaccharide enhances apoptosis of corpus luteum in isolated perfused bovine ovaries in vitro

Lipopolysaccharide (LPS), the endotoxin of Gram-negative bacteria, has detrimental effects on the structure and function of bovine corpus luteum (CL)in vivo. The objective was to investigate whether these effects were mediated directly by LPS orviaLPS-induced release of PGF2α. Bovine ovaries with a mid-cycle CL were collected immediately after slaughter and isolated perfused for 240 min. After 60 min of equilibration, LPS (0.5 μg/ml) was added to the medium of five ovaries, whereas an additional six ovaries were not treated with LPS (control). After 210 min of perfusion, all ovaries were treated with 500 iu of hCG. In the effluent perfusate, concentrations of progesterone (P4) and PGF2αwere measured every 10 and 30 min, respectively. Punch biopsies of the CL were collected every 60 min and used for RT-qPCR to evaluate mRNA expression of receptors for LPS (TLR2,-4) and LH (LHCGR); the cytokineTNFA; steroidogenic (STAR,HSD3B), angiogenic (VEGFA121,FGF2), and vasoactive (EDN1) factors; and factors of prostaglandin synthesis (PGES,PGFS,PTGFR) and apoptosis (CASP3,-8,-9). Treatment with LPS abolished the hCG-induced increase in P4(P≤0.05); however, there was a tendency (P=0.10) for increased release of PGF2αat 70 min after LPS challenge. Furthermore, mRNA abundance ofTLR2,TNFA,CASP3,CASP8,PGES,PGFS, andVEGFA121increased (P≤0.05) after LPS treatment, whereas all other factors remained unchanged (P>0.05). In conclusion, reduced P4responsiveness to hCG in LPS-treated ovariesin vitrowas not due to reduced steroidogenesis, but was attributed to enhanced apoptosis. However, an impact of luteal PGF2αcould not be excluded.

The transcription factor Ap-1 regulates monkey 20α-hydroxysteroid dehydrogenase promoter activity in CHO cells

Background

Monkey 20α-hydroxysteroid dehydrogenase (20α-HSD) is a catabolic enzyme responsible for converting progesterone into biologically inactive 20α-hydroxyprogesterone, thereby playing a key role in the estrous cycle or pregnancy and allowing ovulation and parturition to occur in most mammalian animals. Monkey 20α-HSD was highly abundant in ovarian and placental tissues during the pre-ovulation and pre-parturition phase and was primarily localized in the syncytiotrophoblast of the placenta. In this study, we focused on the molecular characterization of the monkey 20α-HSD promoter region by conducting reporter assays in Chinese hamster ovary (CHO) K1 cells.

Results

A reporter assay using constructs of various lengths of the 5′-flanking region (-890-Luc, -513-Luc, -306-Luc, -273-Luc, and -70-Luc) revealed that a region corresponding to the activator protein 1 (Ap-1) located between -281 and -274 bp was essential for the transcriptional activity. Absence of the Ap-1 site in -273-Luc dramatically decreased the transcription levels to the control levels. When the reporter constructs were co-transfected with Ap-1 (Jun) and specificity protein (Sp-1) genes, the transcription activities of the constructs increased with the exception of -273 and -70, while that of the double construct was reduced compared to that of Ap-1 alone. Furthermore, mutational analysis demonstrated that a putative Ap-1 site played an important role in the expression of the reporter gene. These findings were confirmed by EMSA examining the interactions of the protein Ap-1 in a nuclear extract from CHO-K1 cells and the expression levels of the Ap-1 transcription factor in pre-parturition placenta and CHO-K1 cells. Although mut-1 and mut-2 of Ap-1 bound with nuclear extracts from CHO-K1 cells, the transcriptional activity of mut-3 was almost completely suppressed.

Conclusions

Our results indicate that the Ap-1 site (-281 → -274) (5′-TGTCTCAT-3′) plays a crucial role in the activation of the monkey 20α-HSD gene. Thus, we demonstrated that monkey 20α-HSD promoter activity is regulated by the transcription factor Ap-1 in CHO-K1 cells.

Gene expression and localization of 20α-hydroxysteroid dehydrogenase (HSD) in reproductive tissues during early pregnancy of cattle

The enzyme 20α-hydroxysteroid dehydrogenase (20α-HSD) catalyzes the conversion of progesterone to its inactive form, 20α-hydroxyprogesterone, and this enzyme has an important role in the regulation of luteal function in mammals. It has previously been determined that the 20α-HSD gene is primarily expressed by large luteal cells during the late stage of the estrous cycle. In the present study, the amounts of mRNA were determined in cultured cells of the corpus luteum (CL) cells. The localization of 20α-HSD was also determined in ovaries, placenta, and endometrium during early pregnancy. The amount of 20α-HSD mRNA in cultured luteal cells increased with time and by treatment with the luteolysis agent prostaglandin F2α (PGF2α). Immunofluorescence assays detected increased protein in cultured luteal cells. The 20α-HSD mRNA and protein were present in the ovaries, placenta, and endometrium on Days 30, 60, and 90 of pregnancy. In particular, gene expression was much greater in the ovary than in the placenta and endometrium. Immuno-histochemical analysis indicated that bovine 20α-HSD was primarily localized in ovarian large luteal cells, placental cytotrophoblast villus, and glandular epithelial cells of the endometrium during early pregnancy. Furthermore, in situ analyses demonstrated colocalization of 20α-HSD mRNA and protein. Taken together, results of the present study indicate that 20α-HSD mRNA and protein are co-localized in large luteal cells, the placenta, and the endometrium during early pregnancy, suggesting that 20α-HSD regulates mechanisms involved in the maintenance of early pregnancy.

Expression of aldo-keto reductase 1C23 in the equine corpus luteum in different luteal phases

Regression of the corpus luteum (CL) is characterized by a decay in progesterone (P₄) production (functional luteolysis) and disappearance of luteal tissues (structural luteolysis). In mares, structural luteolysis is thought to be caused by apoptosis of luteal cells, but functional luteolysis is poorly understood. 20α-hydroxysteroid dehydrogenase (20α-HSD) catabolizes P₄ into its biologically inactive form, 20α-hydroxyprogesterone (20α-OHP). In mares, aldo-keto reductase (AKR) 1C23, which is a member of the AKR superfamily, has 20α-HSD activity. To clarify whether AKR1C23 is associated with functional luteolysis in mares, we investigated the expression of AKR1C23 in the CL in different luteal phases. The luteal P₄ concentration and levels of 3β-hydroxysteroid dehydrogenase (3β-HSD) mRNA were higher in the mid luteal phase than in the late and regressed luteal phases (P<0.05), but the level of 3β-HSD protein was higher in the late luteal phase than in the regressed luteal phase (P<0.05). The luteal 20α-OHP concentration and the level of AKR1C23 mRNA were higher in the late luteal phase than in the early and mid luteal phases (P<0.05), and the level of AKR1C23 protein was also highest in the late luteal phase. Taken together, these findings suggest that metabolism of P₄ by AKR1C23 is one of the processes contributing to functional luteolysis in mares.

Androgen deficiency during mid- and late pregnancy alters progesterone production and metabolism in the porcine corpus luteum

We determined whether androgen deficiency induced by flutamide treatment during mid- and late pregnancy affects the functions of the porcine corpus luteum (CL). Pregnant gilts were injected with flutamide between days 43 and 49 (gestation day [GD] 50F), days 83 and 89 (GD90F), or days 101 and 107 (GD108F) of gestation. Antiandrogen treatment increased the luteal progesterone concentration in the GD50F group and decreased progesterone content in the GD90F and GD108F groups. Luteal levels of side-chain cleavage cytochrome P450 (CYP11A1) mRNA and protein were significantly downregulated in the GD90F and GD108F groups as compared with the respective controls. The 3β-hydroxysteroid dehydrogenase/Δ5-Δ4 isomerase (HSD3B) mRNA and protein expression were significantly reduced only in the GD108F group as compared with the control. Decreased luteal 20α-hydroxysteroid dehydrogenase (AKR1C1) mRNA and protein levels were observed in the GD50F group. Thus, androgen deficiency during pregnancy in pigs led to CL dysfunction that is marked by decreased progesterone production. Furthermore, exposure to flutamide during late pregnancy downregulated steroidogenic enzymes (CYP11A1 and HSD3B) in pigs. We conclude that androgens are important regulators of CL function during pregnancy.

Analysis of 20alpha-hydroxysteroid dehydrogenase expression in the corpus luteum of the buffalo cow: effect of prostaglandin F2-alpha treatment on circulating 20alpha-hydroxyprogesterone levels

BACKGROUND

During female reproductive cycles, a rapid fall in circulating progesterone (P4) levels is one of the earliest events that occur during induced luteolysis in mammals. In rodents, it is well recognized that during luteolysis, P4 is catabolized to its inactive metabolite, 20alpha-hydroxyprogesterone (20alpha-OHP) by the action of 20alpha-hydroxysteroid dehydrogenase (20alpha-HSD) enzyme and involves transcription factor, Nur77. Studies have been carried out to examine expression of 20alpha-HSD and its activity in the corpus luteum (CL) of buffalo cow.

METHODS

The expression of 20alpha-HSD across different bovine tissues along with CL was examined by qPCR analysis. Circulating P4 levels were monitored before and during PGF2alpha treatment. Expression of 20alpha-HSD and Nur77 mRNA was determined in CL at different time points post PGF2alpha treatment in buffalo cows. The chromatographic separation of P4 and its metabolite, 20alpha-OHP, in rat and buffalo cow serum samples were performed on reverse phase HPLC system. To further support the findings, 20alpha-HSD enzyme activity was quantitated in cytosolic fraction of CL of both rat and buffalo cow.

RESULTS

Circulating P4 concentration declined rapidly in response to PGF2alpha treatment. HPLC analysis of serum samples did not reveal changes in circulating 20alpha-OHP levels in buffalo cows but serum from pseudo pregnant rats receiving PGF2alpha treatment showed an increased 20alpha-OHP level at 24 h post treatment with accompanying decrease in P4 concentration. qPCR expression of 20alpha-HSD in CL from control and PGF2alpha-treated buffalo cows showed higher expression at 3 and 18 h post treatment, but its specific activity was not altered at different time points post PGF2alpha treatment. The Nur77 expression increased several fold 3 h post PGF2alpha treatment similar to the increased expression observed in the PGF2alpha-treated pseudo pregnant rats which perhaps suggest initiation of activation of apoptotic pathways in response to PGF2alpha treatment.

CONCLUSIONS

The results taken together suggest that synthesis of P4 appears to be primarily affected by PGF2alpha treatment in buffalo cows in contrast to increased metabolism of P4 in rodents.

Flutamide influences placental aldo-keto reductase family 1 member C1 (AKR1C1) expression in pigs

Aldo-keto reductase family 1 member C1 (AKR1C1) catalyses the conversion of progesterone into inactive 20α-dihydroxyprogesterone. It is suggested that AKR1C1 expression in the placenta prevents from the cytotoxic effect of progesterone on foetuses during late pregnancy. The aim of the study was to determine whether the anti-androgen flutamide administered during late pregnancy (83-89 days of gestation) or before parturition (101-107 days of gestation) influences AKR1C1 expression in the porcine placenta. AKR1C1 mRNA and protein levels were measured using real-time PCR and western blotting, respectively. Immunolocalization of AKR1C1 within placentas was also performed. Flutamide significantly increased AKR1C1 mRNA (p = 0.008) and protein (p = 0.019) expression only during the pre-parturient period in pigs. AKR1C1 protein was immunolocalized in the epithelial and stromal cells of foetal and maternal part of placenta at both stages of gestation. Following flutamide treatment, the intensity of staining was higher (p = 0.045) on day 108 of gestation. In conclusion, porcine placental AKR1C1 expression seems to be regulated by an androgen signalling pathway and may be involved in foetal survival by preventing the detrimental effect of progesterone.

Ovarian and placental expression of 20α-hydroxysteroid dehydrogenase during pregnancy in deer

The enzyme 20α-hydroxysteroid dehydrogenase (20α-HSD) catalyzes the conversion of progesterone to its inactive form, 20α-hydroxyprogesterone. This enzyme has been shown to play a critical role in the regulation of luteal function in experimental animals. In this study, we cloned and expressed the gene encoding elk deer 20α-HSD from reproductive placental and ovarian tissues. PCR, 3'- and 5'-RACE, and northern blot analysis were performed for the cloning and characterization of deer 20α-HSD gene. We expressed recombinant deer 20α-HSD protein and used western blot analysis to determine protein expression levels in the placenta and ovary during pregnancy. The full cDNA sequence of 20α-HSD was used to clone an open reading frame encoding 323 amino acids and consisting of 1142 bp. The nucleotide sequence of deer 20α-HSD showed high homology with the sequences of the bovine (96%), goat (96%), and human (83%) 20α-HSD genes. 20α-HSD mRNA was strongly expressed in the placenta on days 30, 60, and 70 of pregnancy. A high level of the protein was also detected in the placenta but not in fetal skin tissue. The recombinant 20α-HSD protein produced in mammalian cells and bacterial systems had a molecular weight of approximately 37-kDa. The deer 20α-HSD protein signal was specifically localized in the basal part of the primary chorionic villi and chorionic stem villus of the placenta during early pregnancy. The 20α-HSD protein was also intensively localized in the larger luteal cells of the corpus luteum during pregnancy.